I am using Ubuntu Studio 12.04 although I have noticed the same in other 12.04 variants.
The dashboard of Ubuntu One says that I have used up 25Gigs of my 25Gigs storage subscription. I am nowhere near the 25Gigs.
Does anyone have any suggestions ?
The quota being misreported should not be an issue in newer installs; it's entirely possible you have a lot more content synced from for example your phone or your tablet than you are aware of, if you have enabled automatic syncing from any of those devices. Failing that, please do get in touch with support as suggested.